1. Field of the Invention
The present invention relates generally to the field of dental instruments, and more particularly, relates to an anti-fog type of dental mirror including a self-contained, portable, rechargeable energy source.
2. Discussion of the Prior Art
Mouth type mirrors or dental mirrors have long been in use by dentists and to a lesser extent, by physicians for conducting detailed examinations within a patient's mouth. Most frequently, the prior art type of dental mirrors have traditionally included an elongate handle having an angled, reflecting surface or mirror affixed at one end thereof. The entire instrument was sturdily constructed and was fabricated of materials suitable for sterilization whereby the device could repeatedly be employed for use with numerous patients with complete safety by simply adhering to recognized hygienic standards.
More recently, prior workers in the art have been developing dental mirrors having electrical components incorporated therein in efforts to improve operating capabilities. For example, in U.S. Pat. No. 1,750,194, Rydman disclosed a dental mirror comprising a tubular element or body having a battery accommodated therewithin. An electric light bulb was positioned forwardly of the body whereby light rays generated by the electric lamp could be directed by a reflector upon the forwardly positioned mirror.
In U.S. Pat. No. 2,428,975, Lamb discloses an illuminated dental mirror which includes generally a hollow, cylindrical body within which is housed a small dry cell battery and a flashlight type bulb. A transparent light transmitting member secures over the lamp, and at the remote end thereof, there is positioned a mirror for examination purposes. The light transmitting member is coated to prevent the escape of light in all but the desired direction.
Densten, U.S. Pat. No. 2,120,091 discloses a fogless dental mirror which includes generally a hollow handle which supports a forwardly positioned mirror. The stem of the handle is hollow and contains a heating element in the form of a resistance wire. A coupling receives heat from the conducting wire and is provided with a threaded connection to the mirror stem. The heat thus imparted to the instrument by the heating unit maintains the temperature of the mirror at substantially the same temperature as that of the mouth of the patient.
In U.S. Pat. No. 1,934,110, Wilson discloses a non-frosting type of dental mirror having a resistance type heater mounted within a metallic sleeve immediately beneath the reflecting mirror.
Harvey, et al, U.S. Pat. No. 4,568,281 discloses a heated dental mirror to prevent fogging including a mirror and a self-temperature regulated electronic heating element positioned immediately adjacent to the mirror. The device includes the necessary circuitry to precisely maintain the temperature of the mirror within a selected temperature range.
While the inventors of the above cited devices and others have generally addressed the problem of providing a non-fog type of oral examining dental mirror, such devices have proved to be relatively costly in construction, difficult to sterilize and in some instances, could possibly create safety problems due to direct connection to the usual 110 volt alternating current electrical power supply. Accordingly, the need remains to provide an improved, heated dental mirror that is simple in construction, completely safe in operation, readily rechargeable, and capable of easy sterilization, whereby the instrument can be constantly available for substantially continuous use with a plurality of patients.